Dual screens problem, nvidia

Hi all!

I use dual monitor setup. Recently I upgraded my Kubuntu 12.04 to 12.10. Since then I have a problem with my screens. They are randomly turning off and on. I mean that:

1. I boot my laptop - it starts with both screens properly set
2. I work, and then go away from laptop for a while. Afer I'm back there is only one monitor active (it's random which one), and all windows and panels are moved to it
3. I use nvidia configuration tool to activate disabled monitor, then I work again using dual screens
4. then... go back to point 2.

I thought that monitors are turning off as an effect of some power saver but Today monitors were switching during my work. I have no idea on what is going on.

I tried to remove xorg.conf - single effect was that after system reboot monitors started with the same view, so I had to manually reconfigure it every time. After that i saved my "preffered configuration" to xorg.conf but it only affected how screens are set up after system reboot (it's ok after reboot).